Difficulties arise in the construction of awnings of this type when the support arms are rotated about an angle of more than 90.degree., since, then, forces applied against the arms of the awning, upon roll-up of the awning web, prevent lifting of the arms of the web of the awning, thus interfering with proper placement of the arms in vertical position. Awnings of this type also are deemed to be subject to wind damage, since winds may balloon out an awning which has been extended, and may cause violent flipping upwardly of the awning web. This may cause damage to the awning and/or the adjacent building or window constructions, and, additionally, interferes with the use to which the awning is intended to be put.